1. Field of the Invention
The invention relates in general to a liquid crystal display, and more particularly to a liquid crystal display with wide viewing angle.
2. Description of the Related Art
The most commonly seen large size commercial liquid crystal displays are such as twisted nematic (TN) display, In-plane switching (IPS) display, and multi-domain vertical alignment (MVA) display. The biggest problem with the TN display is the viewing angle being too narrow, and particularly grey level inversion will occur when the downward angle of visibility is about 30 degrees. In comparison with the TN display, the IPS display or the MVA display provides wider viewing angle but incurs higher manufacturing cost than the TN display. Since the transmittance of the IPS display or the MVA display is only about 60˜80% of that of the TN display, the brightness of the backlight module needs to be increased. Consequently, the manufacturing cost and power consumption of the backlight module increase and the problem of poor heat dissipation arises.
Although the use of wide viewing compensation film may resolve the viewing angle problem for the TN display by increasing the left/right viewing angles to 140 degrees and the top/down viewing angles to 120 degrees, the problem of grey level inversion still left unresolved. In the application of large outdoor advertising billboards whose viewers are standing under the billboards, the display needs the function of displaying the advertisement downwards more than the function of displaying the advertisement in a wide viewing angle. Particularly, the large size outdoor advertising billboards need even higher brightness, so the heat dissipation for the lamp tubes of the backlight module becomes more important.